erl-watch

Erlang application to watch and reload changed beam files into an erlang node. Only loads beam files that are in a directory returned by code:get_path() after removing code:lib_dir() applications.

Depends on fswatch for notifications and therefore scales for large projects.

The environment variable WATCH_DIRS a : separated list of directories controls which directories to watch. Changing WATCH_DIRS requires the watch application to be restarted.

This application does not watch and recompile changes to sources because:

• build systems and commands vary wildly between projects.
• recompiling does not need an erlang node.

Using with rebar

Add as a dependency to application and ensure the application is started. Dynamic Rebar Configuration might be useful here.

Using directly

• compile using make compile
• add ebin directory to your code path e.g., erl -pa .../erl-watch/ebin' -pa ...
• application:start(watch)

Example Usage

cat .../rel/riak/.erlang

%% Adding current projects ebin directories
[code:add_patha(Dep) || Dep <- filelib:wildcard("../../deps/*/ebin")].
[code:add_patha(Dep) || Dep <- filelib:wildcard("../../apps/*/ebin")].
[code:add_patha(Dep) || Dep <- filelib:wildcard("../deps/*/ebin")].
[code:add_patha(Dep) || Dep <- filelib:wildcard("../apps/*/ebin")].
[code:add_patha(Dep) || Dep <- filelib:wildcard("deps/*/ebin")].
[code:add_patha(Dep) || Dep <- filelib:wildcard("apps/*/ebin")].
[code:add_patha(Dep) || Dep <- filelib:wildcard("ebin")].

%% Starting applications
application:start(watch).

WATCH_DIRS=$(pwd) .../rel/riak/bin/riak console # WATCH_DIRS=<dir1>:<dir2> watches <dir1> and <dir2> for changes

Suggestion for Auto-recompilation

I use watchdog like this:

 CMD='rebar compile'
 watchmedo shell-command \
          --patterns="*.erl;*.hrl;*.dot" \
          --wait \
          --recursive \
          --command="${CMD}"